An examination of the role of transcription and translation in the differentiation of amebae of Naegleria gruberi into flagellates is being carried out along two main routes. In the first case the control of messenger RNA synthesis for flagellar tubulin is being studied by in vitro translation. This work aims at establishing the level at which tubulin synthesis is controlled during differentiation. The second major area of investigation involves the synthesis and assembly of flagellar components. This work is exploiting our ability to induce multiple flagella by a temperature shock. It involves a detailed examination of the role of transcription, translation and assembly processes in determining the final cell structure.